This project focuses on long-term consequences of individual differences in physical, social, and affective functioning. One study is concerned with the ways certain signs of arousal or irritability in the first months of life are related to measures of the child's temperament, expressiveness, and physiology at later ages. Preliminary results indicate that irritability, emotional expressiveness, and fear of novelty predict subsequent behavioral inhibition. Cortisol levels increase with age, vary as a function of diurnal rhythms, and increase following stressful laboratory procedures. Uninhibited children had lower cortisol levels then inhibited children. In a second project we are studying the effects of maternal behavior, maternal characteristics, family patterns, and infant characteristics on the socioemotional development of lower-class Hispanic children, developing culturally-sensitive criteria for evaluating normative social behavior and development.